There are a couple of options for doing this.
One version would be to use Zorro 2 to cut through in one go and then I'd use Fixit 101 to repair the missing faces.
The components will all become unique, note I grouped them to contain the cut within the group, otherwise it will slice through your whole model.
I has three goes at showing the context menu for Fixit correctly, so ignore the extra clicking.
https://i.imgur.com/toAFYCL.gif